This invention relates to ultrasonic imaging and Doppler effect measuring method and apparatus for real-time imaging and quantitative measurement of volume flow in a vessel, such as a blood vessel.
Combinations of B-scan imaging and pulsed Dopper motion detecting means for use in the display of a B-scan image together with a blood flow velocity profile are well known as disclosed, for example, in U.S. Pat. No. 4,141,347 by Philip S. Green et al, issued Feb. 27, 1979, and in an article entitled "Ultrasonic Duplex Echo-Doppler Scanner", Barber et al, IEEE Transactions on Biomedical Engineering, Vol. BME-21, No. 2, March 1974, pp. 109-113. With these arrangements, only qualitative, not quantitive, real time blood volume flow measurements are possible. Quantitative measures of blood volume flow are highly desirable for assessment of vascular disease due to atherosclerosis or other causes.
Method and apparatus for the quantitative measurement of volumetric blood flow also are known as shown in the following U.S. Pat. Nos.: 3,498,290--Shaw et al; 3,896,788--Sato; 3,901,077--McCarty et al; 3,977,247--Hassler; 4,067,236--Hottinger; 4,095,597--Hassler; 4,103,679--Aronson; 4,182,173--Papadofrangakis et al; 4,227,407--Drost; and 4,257,278--Papadofrangakis et al. Publications showing quantitative measurement of volumetric blood flow include: "Human Carotid Artery Diameter and Flow by a Non-invasive Technique", Olson and Cooke, Med. Instr. V 9 #2, March-April 1975, pp. 99-101; "A Non-destructive Ultrasonic Technique to Measure Diameter and Blood Flow in Arteries', Olson and Cooke, IEEE Trans. on Biomed. Engr., Vol. BME-21, No. 2, March 1974, pp. 168-171; and "Pulsed Ultrasonic Doppler Blood-Flow Sensing", Baker, IEEE Trans. on Sonics and Ultrasonics, Vol. SU-17, #3, July 1970, pp. 170-184. Prior art volumetric blood flow measuring schemes, often are of complex design and/or provide highly inaccurate quantitative measurements for different reasons. With some systems, a measure of the cross-sectional area of the vessel is required together with blood velocity measurements, for use in calculating volumetric flow. With such arrangements, great difficulty often is encountered in obtaining accurate real-time cross-sectional area measurements.